1. Electron Density and Reactivity:
* Alkenes: The double bond in alkenes contains a localized region of high electron density. This makes the electrons in the double bond susceptible to attack by electrophiles (electron-seeking species).
* Alkanes: Alkanes only have single bonds, which are relatively stable and less prone to attack.
2. Pi Bond:
* Alkenes: The double bond consists of a sigma bond (strong) and a pi bond (weaker). The pi bond is less stable and more easily broken, making the molecule more reactive.
* Alkanes: Alkanes only have sigma bonds, which are stronger and less likely to break.
3. Electrophilic Attack:
* Alkenes: The high electron density in the double bond attracts electrophiles. Electrophiles can attack the double bond, causing it to break and form new bonds.
* Alkanes: Alkanes do not readily undergo electrophilic attack due to the lack of easily accessible electron density.
4. Addition Reactions:
* Alkenes: Alkenes readily undergo addition reactions, where the double bond is broken and new atoms are added to the carbon chain. This is a key characteristic that makes them more reactive.
* Alkanes: Alkanes primarily undergo substitution reactions, where one atom or group is replaced by another. These reactions generally require higher temperatures and more extreme conditions.
In Summary:
The presence of the double bond in alkenes makes them more reactive than alkanes. This is due to the higher electron density, weaker pi bond, and the ability to readily undergo electrophilic attack and addition reactions.
